Thread rolling device



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r71 ARD E LMER B\{05EPH United States Patent THREAD ROLLING DEVICE Elmer '1. Scott and Joseph G. Willard, Worcester, Mass., assignors to Reed Rolled ThreadDie Company, Holden, Mass, a corporation of Massachusetts Application September 27, 1954, Serial No. 458,394 9 Claims. (Cl. 80-6) This invention relates to a thread rolling device, and more particularly to improvements in a device having freely rotatable die rolls forced by a reciprocable member to penetrate a positively rotated piece of work, as described in the copending application, Serial No. 231,- 560 now U. S. patent to Scott, No. 2,704,950, granted on March 29, 1955.

A device of this type is customarily mounted on an automatic screw machine, turret lathe or other suitable machine tool and arranged to roll a thread, a knurled surface or other die rolled configuration in a cylindrical work piece which is positively rotated by the machine tool headstock While the dies are forced directly into the work by movements of a reciprocable member on the machine tool.

The primary object of this invention is to provide a device of this class which will roll a thread accurately and by a positive direct in-feed of the die rolls into the work piece, and wherein the separate rolls are moved positively and equally by. a cam action governed by movement of the machine tool reciprocable member.

A further object is to provide a device of this type wherein two rolls are rotatably mounted on pivoted arms, and cams are so arranged as to move these arms and force the rolls into the work in accordance with the machine tool operation.

Another object is to provide a thread rolling device in which the roll supporting arms may beindividually adjusted relative to the work axis so that the movement of the arms will force the rolls through equal distances 1 into the work. Other objects will be apparent in the following disclosure.

In accordance with this invention, the thread rolling device comprises two bodies herein termed plates, which are relatively movable angularly with reference to the axis of the work, and one of the plates carries swinging arms arranged to hold the dies on opposite sides of thework and the other plate has a cam part moved by the reciprocable member of the machine tool which cooperates with a cam part on an arm and swings the arm to force its die roll positively into the rotatably driven. work. The term thread includes a knurled surface and other configurations formed by rolling dies.

Referring to the drawings illustrating embodiments of this invention:

Fig. l is a perspective view of a preferred form of this device;

Fig.2 is an exploded perspective view of the parts thereof;

Fig. 3 is a side elevation of the device of Fig. 1, partly broken away to show details of construction;

Fig. 4 is a front elevation showing the normal location of the parts prior to a rolling operation;

Fig. 5 is a similar elevation with the parts in a final rolling position;

Fig. 6 is a perspective view, partly broken away, of a modification;

Fig.7 is a view of one end of the device of Fig.6;

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Fig. 8 is a view of the opposite end of the device; and- Fig. 9 is a fragmentary sectional detail taken on the line 9-9 of Fig. 7.

My preferred modification shown in Figs. 1 to 5 inclusive is a structure intended to be so mounted on a machine tool that its freely rotatable dies will grip and roll a positively rotated work piece therebetween. It includes a hollow shank 10 shaped to be mounted on a stationary part of the machine in alignment with the work axis. The shank has a stationary body or plate 11 integrally secured or fixed to it at right angles to its axis. A second member 12 is a plate having a central, cylindrical hole therein so located that the plate may be rotatably or oscillatively mounted for movement about the work axis, and it is preferably mounted for rotation on an outer cylindrical surface of the shank 10. The two plates have inner opposed parallel faces substantially in contact which are arranged to permit a limited oscillative movement of the rocking plate 12. This plate is adapted to be moved in one direction by means of an adjustable set screw 13, which may be engaged and moved by a suitably oscillated pusher member 14 on the machine tool. The screw 13 is threaded into the movable member 12, as shown, and it may be adjusted to locate the rolls in a required starting position for penetration into the work. Thepusher 14 may, of course, contact directly with a contact face on plate 12, if the adjustment is not needed.

Each die roll 15 is mounted on a rocking arm 16 which has a yoke construction for carrying the roll. The yoke support for the die roll is provided by an opening or recess 17 in the inner side of the supporting arm 16 (Fig. l) which is of suitable size to accommodate die rolls of various lengths and diameters. The die rolls are rotatably mounted in axial parallelism on removable pins 19 fixed in aligned holes in the spaced portions of the arms on opposite sides of the recesses 17. The rocking die roll arms 16 have studs 2t} fixed in and projecting laterally from the arms near their outer ends and parallel with the axes of the die rolls and the shank 10. These studs are shaped as shown and insertable into bearing holes 21 in bosses 22 (Fig. 2) projecting laterally toi are moved circumterentially around and radially of the wards the plate 11 from diagonally opposite corner portions of the rocking member 12. The studs 20 are equidistant from the work axis. A lock nut 24 (Fig. 3) on the outer right hand end of each stud 20 bears against a shoulder on the stud and the outer plane face of plate 12 and holds the arm 16 assembled against the adjacent face of the stationary plate 11. This plate is substantially S-shaped or cut away at diagonally opposite corners (Fig. 4) to provide space for assembly and] a limited lateral movement of the studs 20 when the plate member 12 is rocked.

The plate 12 is rocked clockwise by the reciprocable machine tool arm 14, and the pins or studs 20 are thereby revolved in an arc and so carry the roll supports or arms 16 in the same direction (Figs. 4 and 5). A cam action is provided to cause the rocking movement of member 12 and arm supports 20 to move the die rolls' inwardly. To this end, parts 11 and 16 are provided with relatively movable cam members which insure that rocking the plate causes the die roll carrying arms to move inwardly. As shown, the stationary body 11 is provided with two lugs 26 projecting laterally from its outer ends. Each lug has an inner rounded face and is shaped to lie over an outer cam face 27 formed by a wedge-shaped corner portion 28 (Fig. 2) of the die roll carrier arm 16. A cam follower screw 29 is adjustably threaded through each of the opposed lugs 26 where it may contact with the cam face 27 of the swinging die roll yoke 16. Thus as the plate 12 is rocked the die rolls vtorkastheyareforced inwardly. That is, the eccentric mounting of each rocking arm permits the die roll to be swung inwardly as it is dragged around clockwise circumferentially of the workpiece. The plate 11 audits lugs 26 are stationary, and the 'wedgeeshapedxfaces 27 of cam parts 28 are drawn beneath the; faces of lugs 26- .or acrosszthe ends of. screws 29., :if itheyzproject'tfor the purpose, and the cam faces .27'cause their associated.

die rolls .to move inwardly in accordance with :the .shapes' of the cams.

The vtwo rocking arms .116 which carry the the rolls have their .carn faces 27 held against {the iSBt :screws 29- by means of :helical springs .30 (Big. 3.), each :of is suitably secured ,at one end to the lock .nut 24 andJlat the other end to .the shank 10. The two springs wrap around the locking nuts 24 and around the shank and their outer ends are inserted in holes drilled into the faces of the nuts and shank. The coils of the springs are so arranged around the suitably threaded nuts 24 "and the shank 10 as to urge the rocking arms 16 outwardly against the adjustable set screws 29. Hence, when the rocking member 12 is moved in a clockwise direction from the position of Fig. 4 towards the final position of Fig. .5, the arms 16 have their cam faces 27 dragged across the rounded faces of the cam follower .set screws 29 and towards the high points of the wedge-shaped portions 28 of the arms 16. Each cam face is so shaped that this endwise movement of the arm 16 causes the. die roll l to be moved inwardly at a required :rate and movement toward the axis of the work W (Fig. 5;) and thus to penetrate the work and roll a thread thereon. The rate of die movement is determined by the shape of the .cam face and may be such as to provide a gradual dying out penetration after a required variable or :fixed rate of penetration of the work. The rocking arms .16 of the device are reversely symmetrical .in shape and position, .as shown in the drawings, .so that the clockwise movement of the plate 12 forces the die rolls equally toward the work axis.

The set screws 29 are separately adjusted prior :to operation of the device, so that each roll may just .contact .the surface of a cylindrical work piece prior to the starting of the thread rolling operation. Thus, the rocking .motionof the member 12 will force the die rolls equallyinto the work. The springs SO -oppose this making movement and so will return the -rooking plate 12 fromgits final position of Fig. 5 to the starting position of.-Fig. 4;as;soon as the pressure :of the machine tool arm 14 is :released.

In ithe modificatiomof Figs. '6 .to 9 inclusive, -,the .two die .rolls .40 :are moved by cam rocked arms carried :on opposite sidesiof thev rocking plate '41 in accordance with the above described principles; but in this modification, therolls are each mounted on -a yoke 42 on one Side of the plate and the .associatedicam actuated arm 43 is on the other side. That is, the die roll support .and the cam actuated :arm may be considered as an integral double crank having two .connected lever arms, .one being a yoke support .42 arranged .to carry the rolls and the other being a cam operated lever 43. These two .crank arms 42 and 43 are arranged to be rocked by a cam plate 44 which is secured to the-shank .45 that is to be heldfixed on the machine tool. The two arms 42 and 43 may be rigidly secured together by a suitable construction, such as the stud'46 (Fig. v9;) which is .rockingly mountedina bearingtin plate 41 andtis connected to the arm 42 .by a ,set screw 47 and to ,the cam arm 43 by a nut 48 threaded on a reduced end of the stud 46 and serving ito .-hold1.the.cam lever-against a shoulder on an ed Portion .of the stud 46.

in .1his-.e.onstruction,.=the .eam plate .44 is afixed to or integrabwith zthets'hank 45 corresponding with :the shank rof-iEig. .1; of athe above described modification. These parts mhand .45.;may 'rbe formeduas "separate z-pieces, as

shown in-lEig. 9, inn-which the cam plate is provided with .a central "opening carrying .the projecting shank '45, andit is held locked against a shoulder on an enlarged end portion of the shank 45 by means of a split clamp nut 50 suitably threaded on the shank and clampingly secured in place by a set screw 51 (Fig. 6) threaded through the nut and set against the shank.

Each rocking arm 42 which carries a die roll is arranged at such an angle that its die roll is mounted for substantially radial movement toward the center of the work 'W when its associated cam .arm 43 is rocked. The mounting studs 46 which carry the cam and die roll arms 42 are arranged near the corners of the rectangular .rocking plate 41, and the pins 52 which support the die rolls in the bifurcated or yoke arms .42are axially parallel with one another and with the axis of the work W which is rotatably mounted therebetween on the headstock or other suitable part of the machine tool. As in the Fig. 1 construction, the shank 45 is hollow so that the work W may be passed therethrough as may be required in rollingoperation.

"Ihestationary-cam plate 44, asshown in Figs. 6 and '8, has cam surfaces 55 which .are arranged to bear either against the inner faces of the arms 43 or preferably against adjustable set screws 56 threaded into the arms 43. These two set screws 56 are separately adjustable cam followers, so that the :die rolls may be individually adjusted relative to the work taxis. =In .the closed position, the cam face 55 and the inner face of the rocking arm 45 may be substantially parallel, but as the :plate. 41- is rocked each team face 55 moves across the endof :a set screw 56 and thrusts the latter outwardly. It will be understood that this face 55 may be otherwise shaped so asr-to give a controlled movementof the rocking arm and .dierol'ls moved thereby.

Helical tension springs-57 are suitably secured ratithe'ir ends .to the two rocking arms in such a manner as to hold the arms against the cams. In this construction, each team arm '43 is split at :itsouter end, and one end of the :spring -57 is connected to a screw '58. threaded through that split part. "Theother end of the spring is suitably bentuand locked into a hole 59 (Fig. 8 at the pivot end of the oppositearm 43. The set screw 56 is threaded through the bifurcated portion of the lever 43, and the screw 58 serves todraw the split arms together and clamp the adjustable screw 56 in a desired position after the cam arms and die rolls have been properly adjusted relative to the. work axis.

The eam arm-43 andthe die roll arm 42 may be relatively adjusted angularly, if desired, by releasing the nut- 48and'turnin-g the arms 42 and 43 relatively, after which the looking out 48 is set to hold the parts in a locked position. 'I herocking plate 41 may beprovided with a pusher contact which is pushed by a reciprocable member on the machine tool. .As shown, this may be a :set screw- 60 not shown in Fig. =8, which is suita hly threaded into one corner of the plate '41 and locked in place. By its adjustment, the distance of movement of the die rolls toward the work axis may be varied.

The operations of the two devices will be-apparent in view of the abovedisc'losure. In theconstruction of Figs. 1 to 5, the S-shapedplate -11 is :held stationary by means of a clamp on the machine tool engaging the shank 10, While that plate 11 is heldstationary, the pivoted plate 12 is rotated through a small angle by the machine tool cum'feren'ti'al movement of -the die rollcarriers 1.6 around the work thus forces the cam face 27 of each rockingerm 16 inwardly as :it rides across the end of the opposing cam follower 29 and so moves the die rolls into the work. Thus the die rolls 15 move from the positions of Fig. 4 toward that of Fig. 5 as the rocking body 12 is pushed and the die roll arms are swung inwardly. The return movement of the parts toward the initial position of Fig. 4 is efiected by the helical springs 30 as above described. Since the die rolls are individually adjustable in position relative to the work axis by moving the cam screws 29, each of the die rolls may be brought into proper relation to the work prior to the rolling step.

In the construction of Figs. 6 to 9 the operation is substantially the same, since the swinging member carrying the die roll likewise has a cam contact and the rotary movement of the cam arm 43 causes the roll supporting yoke 42 to be moved inwardly toward the work pieces. The adjustment screw cam follower 56 is for convenience located in the swinging arm 43 but may be arranged in the cam plate 44, if desired. By separately adjusting each screw 56, the die rolls may be independently located relative to the work axis.

It will now be appreciated that the construction of both modifications comprises two relatively movable bodies, herein shown as parallel plates, one of which is held stationary in the machine tool, the other being rocked or rotated through a slight angle about the work axis by a reciprocable member of the machine tool. The freely rotatable die rolls are carried on rocking carrier arms which are pivotally mounted on one of the plates. Each of these rocking arms has a cam member associated therewith which contacts with and is moved by a cam member mounted on the other of the two plates, and the arm and die pivots are so arranged in association with the other parts that the relative rotative movement of the plates will serve to rock the carrier arms and force the associated die rolls into the positively rotated work to roll a thread thereon.

Various modifications may be made in the construction illustrated within the above outlined structure, and it will, therefore, be understood that the above description is to be interpreted as setting forth principles of the invention and preferred embodiments thereof and not as imposing limitations on the appended claims.

We claim:

1. A thread rolling device comprising two parallel plates, one being stationary and having a shank adapted to be fixed on a work rotating machine tool which has a reciprocable member, the other plate being mounted for a limited angular rotation about the work axis by said member, freely rotatable thread rolling die rolls axially parallel with and spaced from the work axis, separate carrier arms supporting the die rolls, pivots for the arms mounted eccentrically on the movable plate equi-distant from its axis, adjustable cam followers fixed on the stationary plate and located outside of the carrier arms, cam faces on the carrier arms having predetermined surface shapes contacting with said cam followers which are shaped to force the arms inwardly when dragged across said cam followers and circumferentially of the work axis by the movable plate and cause a controlled rate of penetration of the work by the die rolls.

2. A thread rolling device according to claim 1 in which the movable plate is rotatively mounted on the shank of and close to one side of the stationary plate, and the carrier arms are mounted on the movable plate adjacent to the opposite side of the stationary plate, the latter being cut away at the corners to form an S-shape, and the carrier pivots projecting through the cut away spaces, the stationary plate having lateral projections which locate the associated cam members over the pivoted carrier arms.

3. A thread rolling device according to claim 1 in which the stationary cam members are separately adjustable cam followers which serve to locate the die rolls individually relative to the work axis.

4. A thread rolling device according to claim 3 in which the stationary plate has lateral projections located over the carrier arms and the adjustable followers are screw threaded into the projections.

5. A thread rolling device comprising a stationary cam plate having a shank adapted to be fixed on a work rotating machine tool which has a reciprocable member, a plate parallel with the cam plate and rotatively mounted on the shank in axial alignment with the work and arranged to be pushed by said member, a set of freely rotatable die rolls, rocking carrier arms supporting said die rolls which are pivotally mounted on the movable plate eccentrically of and equally spaced from its axis, separately adjustable cam followers movable with said arms which cooperate with the cam plate to rock the carrier arms when the movable plate is pushed, and resilient means to hold the cam members against the cam plate and to return the rocking plate to an initial position after a thread rolling operation.

6. A thread rolling device comprising a fixed and a movable plate arranged for a relative rotary movement, a shank projecting outwardly from the fixed plate which is arranged in axial alignment with a work piece and adapted to be mounted on a work rotating machine tool having a reciprocable member, the movable plate being mounted for rotation by said member through a limited angle about the axis of the shank, thread rolling die rolls axially parallel with the work, separate rocking carrier arms supporting the die rolls for free rotation, a pivot for each arm mounted on one of said plates which is axially parallel with, equidistant from and eccentric to the work axis and so arranged that the arm may swing the die roll toward and from the work, a cam member associated with each arm, a cam member carried by the other of said plates, one cam member having an elongated cam surface of predetermined shape, the other cam member being a follower which is slidably movable along said cam surface as the plates are rotated relatively and serves to rock the associated carrier arm and force the die into the work, the shape of said cam surface being predetermined to provide a definite controlled rate of penetration of the die roll into the work when the plates are rotated relatively, and resilient means which holds the adjacent cam members in contact and yieldingly resists the relative rocking movement of the plates.

7. A thread rolling device according to claim 6 in which each cam follower is a separate adjustably mounted member arranged to move the associated die roll initially and separately towards the work axis so as to proyiide for equal penetration of the die rolls into the wor 8. A thread rolling device according to claim 6 in which the die roll carrier arm is pivotally mounted on the rocking plate and the cam follower mounted for movement therewith and the fixed plate has a cam surface cooperating with the cam follower to rock the carrier arm and force the die rolls into the work.

9. A thread rolling device comprising a fixed and a relatively movable plate having opposed parallel surfaces permitting relative rotary movement thereof, a shank projecting outwardly from the fixed plate which is adapted to be fixed in axial alignment with a work piece and mounted on a work rotating machine tool having a reciprocable member, the movable plate being mounted on the shank for rotation by said member through a limited angle about the work axis, thread rolling die rolls axially parallel with the work, separate rocking carrier arms supporting the die rolls for free rotation, pivots which rockingly support the carrier arms on the movable plate, each pivot being axially parallel with and eccentric to the work axis and so arranged that the associated die roll may be swung towards and from the work, said stationary plate having a cam surface thereon, a cam follower slidably engaging said surface, and an arm supporting the cam follower which is rigidly connected with the carrier arm for moving the follower therewith, said cam surface having the die rolls at a controlled ratmof-Work penetration: .11

References Cited in the file of this patent UNITED STATES PATENTS Lain'dis Feb. 20; 1912 Byssheu. Oct; 30, 1934 Ross; .Mat.;2,f 1948 1 Suott ...Mar.' 129, 1955:

FOREIGN 'PATENTS' Sweden- Oct. 12, 1948 Great Britain: .Aug. 11, 1947 I 

